This invention relates generally to mobile communication systems, and particularly to a mobile communication methods for mobile stations, base station controllers and packet data service nodes.
Effective use of radio channels in mobile communication systems can be achieved using packet switching techniques to enable sharing of a radio channel among mobile stations. According to such techniques, when a request for signal transmission or reception is generated, each mobile station uses the assigned radio channel shared with other mobile stations to transmit or receive signals in the form of packets. Further, when there is no such request, the radio channel is freed to enable its use by another mobile station. Moreover, in such techniques, radio channel assignment to mobile stations in which no packet transmission or reception has taken place for a certain time period are canceled.
In conventional mobile communication systems, if a request for signal transmission or reception occurs in a mobile station canceled for radio channel assignment, it is necessary to begin with assignment of a radio channel to that mobile station. But there is a possibility that there is no free radio channel. In addition, in a mobile communication system, as a mobile station moves from one cell to another, the mobile station must be assigned a radio channel by the radio base station controlling the destination cell but again there is a possibility that there is no free radio channel. This may lead to problems in communication quality assurance for communications that require high reliability, such as electronic commerce.
What is needed are techniques for maintaining an assigned radio channel between mobile and non mobile units in a packet based mobile communications systems.